JPH0248877B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to means for emitting a rate measurement signal in an electronic timepiece with a matrix drive display.

BACKGROUND OF THE INVENTION Electronic watches that count the frequency of a crystal oscillator and digitally display the counted value as time on an electro-optical display such as a liquid crystal display having a selection pattern of numbers are well known. It is also well known that methods for driving display patterns in electro-optical display devices such as liquid crystal display devices include a so-called static drive method and a matrix drive method (also called a dynamic drive method). In the static drive method, one of a pair of transparent electrode films for each segment sandwiching the liquid crystal material layer of a liquid crystal cell is combined into one terminal and used as a common electrode, and a rectangular potential waveform with a constant amplitude of several tens of Hz is applied. On the other hand, terminals are drawn out for each segment constituting the display pattern, and the segments that are not to be displayed are given a potential waveform of the same amplitude and phase as the potential waveform of the common electrode, while the segments that are to be displayed are given a potential waveform of the opposite phase. Thus, only the liquid crystal material layer corresponding to the segment portion to be displayed is placed in the driving electric field. On the other hand, in the matrix drive method, the common electrode is not integrated into one electrode but is divided into several pieces (each is called a row electrode), and conversely, the segment electrodes are not all made discrete;
One electrode corresponding to each row electrode is connected together to form a group (each electrode is called a column electrode). The potential waveform applied to the row electrodes is created so that only a group of segments belonging to one row can be lit and displayed at a time, and this state appears in each row in a time-sharing manner in a fast cycle. Different potential waveforms are applied to the column electrodes depending on which of the segments included in the column electrodes overlaps with the row electrodes to be driven. The potential waveforms applied to these row or column electrodes utilize the fact that the behavior of the liquid crystal substance is approximately dependent on the effective value (root mean square) of the driving potential difference waveform, and as a result, the segment to be displayed (lit) A voltage effective value greater than the threshold value for lighting is applied to the liquid crystal substance corresponding to the segment, and an effective voltage value smaller than the threshold value is applied to the liquid crystal substance corresponding to the segment to be hidden (extinguished). Generally, the waveform is a complex step-like waveform that is a combination of several potential levels prepared in advance.

The driving method of electronic wristwatches with liquid crystal displays that have been put into practical use in the past has been based on liquid crystal materials because the power supply circuit and drive circuit configuration are simple, and the display does not need to be highly stable as long as the threshold voltage is low. A static drive is used because it allows for easy selection of LCD cells and tolerances for processing accuracy of liquid crystal display cells.
In the matrix drive method, the total number of electrode terminals that must be drawn out from the display device is about half that of the static drive method, and the connection with the drive circuit is simplified, reducing the manufacturing cost of watches and improving reliability. Since it has great merits such as being able to display characters, pictures, and multi-digit numbers in multiple segments, it is thought that it will be put into practical use in the near future as the level of circuit technology and liquid crystal cell manufacturing technology improves. Liquid crystal matrix drives are already a common technology in electronic desktop calculators.

Now, even in electronic wristwatches, it is necessary for after-sales service to be able to check the rate at any time, and it is desirable to be able to retrieve the rate signal without opening the back cover of the watch. In conventional LCD watches, when a metal plate is installed close to the windshield of the display surface from outside the watch case, a weak static drive potential change is induced on this plate, so this can be amplified. It was possible to use this as a rate signal. However, when trying to use the same method in the matrix drive method, the problem is that the detection level becomes unstable and the sensitivity decreases due to the complexity of the voltage waveform, which rapidly transitions through many voltage levels, and the small number of segments that take the same waveform. However, the rate measuring device did not work properly.

In the present invention, one of the keys to practical application of the matrix drive system in watches, especially wristwatches, is as follows.
The purpose of this paper is to focus on the above-mentioned drawbacks and to provide a solution to them.

This will be explained below based on the drawings.

1 and 2 are a front view and a main sectional view of a wristwatch movement according to an embodiment of the present invention, and 1 is a liquid crystal display in which a liquid crystal material (not shown) is sandwiched between a transparent upper substrate 1a and a lower substrate 1b. display cell,
2 is a power supply battery; 3 is a lead terminal pattern of a display pattern drive electrode group provided on the lower surface of the upper substrate 1a;
Reference numeral 4 is a holder made of plastic etc. on which all the elements constituting the movement are mounted, 5 and 6 are display cell holding plates, 7 and 8 are battery holding plates, 9 is an integrated circuit chip, 10 is other external parts, 11 12 is a circuit board having a wiring pattern for connecting electronic components; 12 is a multi-point connector member for connecting the circuit and the display electrode terminal 3; In this structure, the display cell 1 and battery 2 are arranged side by side, making it possible to make the wristwatch as thin as possible. In addition, since the display electrode terminal 3 is placed on the edge of the display device 1 that does not come into contact with the battery, the display pattern can be positioned almost in the center of the watch as shown in the figure, resulting in a watch that is both reasonable in design and easy to read. Ta. The latter feature was made possible by reducing the number of terminals by making the display matrix-driven, and even though the terminals were concentrated on one edge on the display cell side, the spacing between the electrodes was static drive. The positional accuracy of the electrode pattern and the reliability of the connection with the connector will not be particularly affected, and the total number and density of wiring patterns on the circuit board side will be reduced, allowing for miniaturization. Design can be done without forcing tolerances, and the number of connections between the IC chip and the board pattern is reduced, resulting in a reduction in chip price due to chip miniaturization, a reduction in bonding work hours, and improved reliability. 13 is a button for operating a switch for setting the display to rate measurement mode, which will be described later, from outside the watch; 14 is a plate-shaped conductor antenna connected to the clock circuit and for emitting rate signals to the outside; It is located on the back cover side of the watch body, opposite to the display surface. The shape of this conductor does not have to be a flat plate shape, but may be a ring shape or a sag-like shape, and instead of one conductor, two conductors driven in opposite phases may be placed close to each other. (The electrode structure of a statically driven display device is similar to this.) Then, place the watch, display side up, on a pick-up for a rate measuring device in which electric field detection electrodes are embedded, or press the button 13 to turn the watch on. Simply set it to measurement mode and place it on a pick-up with the display facing down, and you can easily get into the rate measurement position.

An example of an electrode pattern for matrix drive is shown for reference in FIGS. 3 and 4. All the upper electrode patterns shown in FIG. is directly connected to These are column electrodes. The lower electrode pattern shown in FIG. 4 is provided on the upper surface of the lower substrate 1b, and is connected to terminals X, Y, and Z of the upper substrate through silver dots 3a. These are the row electrodes. The total number of terminals is 12, but if the same display is statically driven, a total of 26 electrodes are required: 1 common electrode; 1 number segment + 7 x 3 = 22; 1 each for colon, AM, and PM. Even though the number of digits is small, it becomes difficult to arrange terminals only on one side of the display cell. Even if the number of display digits increases further, the number of column electrodes increases by only three per seven segments (in the case of three-row drive), so it will not be a big burden.

FIG. 5 shows a block diagram of a wristwatch circuit system according to an embodiment of the present invention. The main parts are, of course, integrated into monolithic circuits.
21 is, for example, a 32768Hz crystal oscillator, 22 is a frequency dividing circuit that creates clock signals and clock signals that define circuit operation, 23 is a time counter that counts time signals to obtain time information, and 24 is a row or column electrode. 25 is a multi-level voltage converter that converts one power supply voltage into several power supply potentials, 26
is a row electrode driver that combines several potential levels and outputs a row electrode potential waveform controlled by a timing pulse.The output is the same as that of the display device 1 in a normal time display state where the display is driven in a matrix. Connected to the X, Y, and Z terminals of the A column electrode driver 27 decodes the contents of the time counter and outputs a corresponding column electrode potential waveform, and its output is normally given to the A to I electrodes. 28 is
This is a rate measuring switch operated by button 13. When this is closed, the timer circuit 29
outputs a constant output to the line 30 for a certain period of time, for example 1 minute.
occurs in 31 is an AND gate that selects one of the voltage levels (preferably one with a large absolute value) and modulates it with the low frequency output (for example, 32 Hz) of the frequency dividing circuit 22 to generate a rectangular wave potential signal; 32 is an inverter that creates an inverted signal of that signal. 3
Reference numeral 2 denotes 12 transmission gates indicated by TG ₁ to TG ₁₂ , which cut off the output of each driver 26, 27 connected to the row or column electrode when a timer output appears on the line 30. , has the effect of switching between the output of the AND gate 31 or the output of the inverter 32. While there is an output on line 30, there is no longer a time display, but a waveform equivalent to a static drive is applied between all row electrodes and all column electrodes, allowing rate measurement. Furthermore, since the output of the AND gate 31 is directly connected to the transmitting antenna 14, it is also possible to constantly measure the rate. Of course, it is sufficient that only one of the above two types of rate signal sending devices exists. To set the rate measurement state,
It is not necessarily necessary to use a push switch and a timer; the timer 29 may be omitted by using a switch operated by a self-retaining operating member such as a reuse, or by using a jig that allows the button to be held down. Normal rate measurement is a special case that is not normally required, so it only works when the switch is hidden in the battery hatch or when one or more switches are operated in a special manner (for example, long press for more than 10 seconds, combination press, etc.) A switch circuit like this may be provided.

Figure 6 shows an example of the complexity of the matrix drive waveform, where the drive power supply potential is at three levels (+E,
O, -E), and two cycles are shown in each case. X, Y, and Z are the first and second rows, respectively.
The potential waveforms applied to the rows and the third row, each with 1/
The phase is shifted by three periods. S is the potential waveform applied to one of the column electrodes, and So is when all segments connected to that electrode are hidden.
Sx displays only the segment belonging to the X row and hides the others, Sxy displays the two segments belonging to the X and Y rows, and hides the segment belonging to the Z row, Sxz displays the segment belonging to the X row , Z rows are displayed and segments belonging to Y rows are hidden, Sxyz is a column electrode waveform corresponding to the case where all segments belonging to each row are displayed. By shifting the respective phases by 1/3 or 2/3 periods, column electrode waveforms for all other cases not illustrated are obtained.

Figure 7 shows a simplified drive waveform when the display is in the rate measurement state, where Ma is the potential waveform applied to all column electrodes, Mb is the potential waveform applied to all row electrodes, and all segments are It is the same as the static drive waveform for lighting. It is not necessarily necessary to turn on all the segments, just some of them, or even all of them may be turned off in some cases. It is important to drive with a sharp waveform. antenna electrode 1
The same can be said of the voltage waveform supplied to 4. In order to increase detection sensitivity, it is desirable that the antenna electrode is not covered by the metal part of the watch case. The antenna electrode may be provided on the display surface side depending on the case. (For example, it may be provided as a transparent conductive film on the front surface of the display device, or as a ring-shaped metal electrode surrounding the display surface, etc.) As a second embodiment of the present invention, although not particularly shown, the following may be used. Frequency divider circuit 22 in FIG.
For example, take out a signal with a period of 1 second, and use the waveform obtained by differentiating this to modulate a separately prepared power source with a sufficiently high potential to create an extremely narrow spike pulse with a period of 1 second, and apply this to the row electrode. Also, a spike pulse with the sign reversed is applied to the column electrode. These signals are superimposed or inserted into the normal matrix drive output by removing the transmission gate 32 and replacing it with an OR gate. Since this waveform is extremely narrow, the display does not respond, but since the rise is steep, it is possible to detect the rate.

As described above, the present invention provides a timepiece with an antenna conductor for transmitting rate signals, a rate measurement mode that simplifies the display drive waveform, or a rate signal to which the display does not respond to the display drive. This superimposition facilitates rate detection in electronic watches with matrix drive display devices. Furthermore, even in watches that have any of various electro-optical display devices other than liquid crystal displays, such as electrochromic display devices, elastomeric display devices, light-emitting diode display devices, and high dielectric ceramic display devices, the characteristics of the display drive cannot be changed as is. When the electric field detection of rate is not suitable, temporarily switch to a driving state that allows rate detection, provide a separate transmitting antenna electrode and supply a rate signal, or insert a rate signal that cannot respond to the display drive waveform. The method of the invention is effective. The present invention is also applicable to pseudo-analog timepieces that display the time position electro-optically.

[Brief explanation of the drawing]

FIG. 1 is a front view of one embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA, FIGS. 3 and 4 are diagrams showing an example of drive electrodes of a matrix-driven liquid crystal display cell, and FIG.
Figure 6 is a block diagram of a circuit according to an embodiment of the present invention.
The figure shows an example of the matrix drive waveform, and FIG. 7 shows an example of the voltage waveform supplied to the display drive signal or antenna during rate measurement. 1... Display device, 2... Battery, 3... Display electrode terminal,
4... Clock base, 13... Rate measurement mode setting switch button, 14... Rate signal transmission antenna, 28...
Rate measurement mode setting switch, 29... Rate measurement mode fixed timer, 31... Rate signal generation circuit,
X, Y, Z...row electrodes, A, B,...I...column electrodes.

Claims (1)

[Claims] 1. In an electronic watch that normally displays time by applying a voltage waveform for matrix drive to the display electrodes of a liquid crystal display device, the voltage waveform applied to the display electrodes by an external operation is used for rate measurement. An electronic timepiece having a matrix drive display, characterized in that it is equipped with switching circuit means for switching to a static drive waveform prepared in advance for use. 2. The electronic timepiece having a matrix drive display according to claim 1, wherein the static drive waveform is simultaneously applied to a plurality of display electrodes driven in a time-division manner during normal matrix drive.